Heat exchanger core

ABSTRACT

A tube and fin type heat exchanger core made up of unique and identical plate strip structures having formed extrusions, the extrusions nesting when the plates are stacked to form the tubes and the portions of the plates between the extrusions forming the fins. The extrusions form trough-like projections with a number of holes in the bottoms of the trough-like projections to permit the flow of fluid between the plate structures. The walls of the projections have offset portions to serve as spacing means between the plates. A slight crimp or bend is provided in the plate portion between each extrusion to facilitate the assembly of the plate structures regardless of small deviations in the spacing dimensions between extrusions.

United States Patent Ireland et al. 1 1 Nov. 28, 1972 [s 1 HEATEXCHANGER coma: [72] Inventors: Robert G. Ireland, Indianapolis; PfimaryEmminerfiedenck L- Manesofl Fred L. Mauls, Greenwood; Ross W.Teeguarden, lndianapolis, all of 1nd.

Karmazin ..l65/150 X Assistant Examiner'lheophil W. StreuleAttomeyAugustus G. Douvas, William J. Newman and Norton Lesser [57]ABSTRACT portions to serve as spacing means between the plates.

A slight crimp or bend is provided in the plate portion between eachextrusion to facilitate the assembly of the plate structures regardlessof small deviations in the spacing dimensions between extrusions.

2 Clalns, 6 Drawing Figures PATENTEDunvze I972 sum 1 [IF- 2 FIG.3

INVE NTORS Robert G. Ireland Fred L- Munis Ross W. Teeguorden By Attornev HEAT EXCHANGER CORE This invention relates to heat exchangers andmore particularly to heat exchanger cores of the tube and tin type whichinclude individual plate structures making up the heat exchanger core.

A primary objective of this invention is to provide a very low cost heatexchanger without sacrificing operation efficiencies. Todays risinglabor, manufacturing and overhead costs, as well as industrys conversionto automated techniques, dictate the need for a simply constructed heatexchanger, formable with relatively inexpensive materials with a minimumnumber of com ponents and which can be assembled in a variety of ways tomeet different performance requirements. Furthermore, heat exchangercores should have sufficient strength to withstand the extremeconditions to which they can be subjected in vehicular applications, andthe like. It is to meet this combination of requirements which the heatexchanger core and the components therefor embodying this invention aredirected.

SUMMARY OF THE INVENTION The teachings of this invention are embodied ina heat exchanger formed by a plurality of nested stacked platestructures, each of which comprises a plate strip having equisizedtrough-like projections formed therein in equispaced parallel positionstransverse to the longitudinal axis of the strip. The bottoms of theprojections define a plurality of apertures therein to provide for thereinforcement of the long sidewalls as well as cause agitation in theflow of fluid through the tubes formed by the nested projections. As oneaspect of the invention, the walls of the projections are formed withoffsets whereby the opened ends of the projections will receive thebottom ends of the projections of adjacent plate structures in spacedrelationship therewith.

As another aspect of the invention, a crimp or bend is provided acrossthe plate strips in the portions between adjacent projections to providefor easy stacking of the plate structures. In a further aspect of thisinvention, the apertures in the bottom of the trough-like projectionsare asymmetrically located with respect to the longitudinal center ofthe troughs. Thus, when all of the nested plate structures are alignedin the same direction, the apertures will be in alignment to provide aparticular flow pattern, whereas another flow pattern will result whenalternate plate structures are aligned in opposite directions.

Other objects, advantages and features of this invention will becomeapparent upon a further reading of this specification, especially whentaken in view of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a tubeand fin heat exchanger embodying the teachings of this invention;

FIG. 2 is a partial perspective view of one corner of the upper andlower heat exchanger shrouds;

FIG. 3 is a partial section view of the heat exchanger core taken alongthe line 3-3 of FIG. 1;

FIG. 4 is a perspective view of one plate structure for forming a heatexchanger core;

FIG. 5 is a partial plan view of a plate structure; and

FIG. 6 is a perspective view of the upper header plate of the heatexchanger. 1

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. 1, thereis shown a heat exchanger 10 designed for use as an oil cooler for ahigh performance automobile. It consists of a fin and tube type corematrix 12 with an inlet header assembly 14 in cooperative assembly withthe core at its upper end and an outlet header assembly 16 incooperative assembly with the bottom end of the core 12. The core matrix12 comprises a plurality of stacked plate structures 18 havingtrough-like projections 20 (FIG. 3) nesting together, in a manner to behereinafter discussed, to form a fin and tube type assembly. The upperheader includes an upper header plate 22 and an upper header shroud 24,together which form the upper header chamber'26. The upper header plate22 has a number of elongated apertures 30 therein which are incooperative relationship with the formed tubes of the core structure soas to permit distribution of the fluid received at the fluid inlet 32.The lower outlet header assembly 16 comprises a lower header plate 34and a lower header shroud 36, preferably of the identical constructionas the upper shroud 24, together which form the lower header chamber 38.The'lower header plate 34 has a number of elongated apertures 40 definedtherein, which are in cooperative relationship with the formed tubes ofthe core to permit passage of the fluid therethrough to the lower headerchamber 38 where the fluid is collected and transmitted to the outlet42.

The upper and lower shrouds 24, 36 are fastened to their respectiveheader plates 22, 34 by means of rolled outer edges 44, 46 which receivethe outer edges 48, 50 of the respective header plates 22, 34. Therolled edges on the header plates are preferably formed before assemblywith the shrouds 24, 36 and the shrouds then assembled with the headersby sliding the edges 48, 50 into engagement with the rolls 44, 46. Tofacilitate that type of assembly, whether it is to be a manual orautomated function, locator tabs 52, 54 are provided at the end of theheader plates 22, 34 which cooperate with or stops apertures 57 tohelp'locate the longitudinal position of the shrouds with respect to theheader plates and maintain them in their relative position. The headerplates and shrouds may be sealed together around their edges by anyappropriate means such as brazing or welding.

As previously mentioned, the heat exchanger core 12 is made up of anumber of stacked plate structures 18, as may be best seen in FIGS. 3, 4and 5. The plate structures are designed to be simply fabricated fromplain metal strips by simple automated machine processes. All of theplates forming a core are identically constructed so that they can beformed from large rolls of plate strip material 55 and cut to the propersize for stacking to form the heat exchanger core. As indicated earliertrough-like projections 20 are formed in the strip material inequispaced parallel positions aligned transverse to the longitudinalaxis 56 of the plate strip 55. The walls 58 (FIG. 3) have outwardlyspaced offsets 60 therein sothat the bottom portion 62 of eachprojection will nest within the upper portion of the trough-likeprojection of the adjacent lower plate structure. The height along theprojection walls 58 at which the offset 60 is located determines thespacing between the core plates.

The trough-like projections are regularly spaced along the length of theplate strip 55 but, as is well known, it is impossible to maintain exactdimensions therebetween to enable the easy stacking of the nested platestructures. The plate structures are therefore provided with a slightcrimp or bend 66 midway between projections and having an axistransverse to the plate longitudinal axis. Thus when the platestructures 18 are stacked to form the core, there is a certain amount ofgive ineach plate to overcome dimensional differences betweenprojections.

The bottom wall 68 of each trough-like projection 20 defines a pluralityof apertures 70 which are regularly spaced along the length thereof. Theapertures 70 are preferably, but not necessarily, round, having adiameprojections between the two extended length sidewalls 58. The bands72 between the apertures 70 serve a dual purpose in the heat exchangercore. They serve to strengthen the assembly by giving support betweenthe long sides of the trough-like projections, and they also serve asturbulence creators for the fluid flowing through the channels formed bythe stacked projections. Applicants have found it advantageous to offsetthe spacing of the apertures 70 with respect to the longitudinal centerof the plate 18 so that the ones on one side of the longitudinal centerof the trough will be spaced different amounts from the center thanthose on the other side. This permits the plate structures 18 to bestacked with alternate plates rotated l80 in lengthwise orientation sothat the holes 70 of adjacent structures are not aligned. The repeatedchange in flow directions as the fluid flow therethrough results in amixing action which enhances the heat transfer of the core.Alternatively, the plate structures 18 can be assembled with the holesaligned, which might be preferable for some heat exchanger applications.

As can be seen in FIG. 6, the upper header plate 22 has flanges 74around each of the elongated holes 30 at its bottom surface. These areprovided so as to meet with the upper open ends of the trough-likeprojections 20 in the top plate structure 18 forming the heat exchangercore as shown in H6. 3. The apertures 40 in the lower header plate 34are sized to receive only the bottom portion 62 of the bottommost platestructure 18 forming the heat exchanger core 12.

The simple manner in which a heat exchanger of the type described may befabricated and assembled is readily apparent. The plate structures 18can easily be formed from extended lengths of strip material by wellknown automated techniques. The plates can then be I automaticallyassembled, either in the alternate or the aligned manner, since thecrimps 66 between the projections 20 allow for dimension diiferentialsand the offsets on the projection walls 58 serve to determine thespacing between the plates. The core of stacked plate structures canthen be fixed together and sealed by automatic brazing techniques or thelike. As an alternative the header plates and header shrouds may beassembled therewith by automated procedures and the whole heat exchangerstructure sealed together by well known brazing techniques.

While there has been disclosed a preferred embodiment of this invention,it is to be understood that modifications and additions may be madethereto without deviating from the scope of the invention. It istherefore intended to be bound only by the scope of the appended claims.

What is claimed is:

l. A heat exchanger core comprising a plurality of plates of finitewidth, a plurality of equal sized troughlike projections integrallyformed on each plate and located at equal spaced parallel positionsalong a respective axis transverse to the longitudinal axis of therespective plate, each of said trough-like projections defined by spacedside walls, spaced end walls and a bottom planar wall spaced from therespective plate to define an open end adjacent the respective plate,the bottom wall of each projection having a plurality of aperturestherein to define bands between said apertures for rigidifying saidbottom wall, said side walls and end walls of each projection eachhaving an outwardly offset portion adjacent the respective plate toenable the open end of each projection to nestingly receive the bottomwall and a portion of the side and end walls of a respective projectionan an adjacent plate, whereby said plates are stacked to form a corewith the offset portions determining the spacing between said plates,said bottom wall apertures closely spaced along each bottom wall toprovide fluid paths through the projections of each plate with saidapertures located asymmetrically with respect to the longitudinal axisof each plate whereby said plates are either stacked with said aperturesin aligned positions or alternate plates are rotated and stacked withsaid apertures in offset positions for forming either a straight ortortuous fluid communication path through the projections of saidstacked plates, and a bend fonned in each plate spaced between and fromeach pair of said projections forflexure about an axis transverse to therespective plate longitudinal axis for controlling the distance betweeneach projection to compensate for dimensional differences in saidprojections for enabling alignment of the projections of said plates forstacking.

2. In the heat exchanger core claimed in claim 1, a first header plateadjacent one end plate of said stacked plates with said header platehaving a plurality of equally spaced ports each defined by a flangeprojecting from said header plate and corresponding in number, shape anddimension to the open ends of said one end plate projections forenabling each flange to be received in the open end of a respective endplate projection, a second header plate adjacent the opposite end plateof said stacked plates with said second header vplate having equallyspaced apertures therein for receiving the bottom wall and a portion ofthe side and end walls of a respective projection on said opposite endplate, a shroud with a flat peripheral face for each header plate forforming a respective sealed header chamber in conjunction with arespective one of said header plates, a rolled edge on each of saidheader plates for nestingly receiving a respective edge of the flat faceof a respective shroud in response to movement of said shroud along thelongitudinal axis of said plates, locator tabs on said header plates forengaging with stops formed on the flat face of the respective shroud tolimit said movement to thereby locate said shrouds relative said headerplates, means for providing fluid flow into one of said chambers definedby said one header plate and the respective shroud, and means forproviding for the flow of fluid out of the other of said 5 chambersdefined by said other header plate and the respective shroud.

1. A heat exchanger core comprising a plurality of plates of finitewidth, a plurality of equal sized trough-like projections integrallyformed on each plate and located at equal spaced parallel positionsalong a respective axis transverse to the longitudinal axis of therespective plate, each of said troughlike projections defined by spacedsidE walls, spaced end walls and a bottom planar wall spaced from therespective plate to define an open end adjacent the respective plate,the bottom wall of each projection having a plurality of aperturestherein to define bands between said apertures for rigidifying saidbottom wall, said side walls and end walls of each projection eachhaving an outwardly offset portion adjacent the respective plate toenable the open end of each projection to nestingly receive the bottomwall and a portion of the side and end walls of a respective projectionan an adjacent plate, whereby said plates are stacked to form a corewith the offset portions determining the spacing between said plates,said bottom wall apertures closely spaced along each bottom wall toprovide fluid paths through the projections of each plate with saidapertures located asymmetrically with respect to the longitudinal axisof each plate whereby said plates are either stacked with said aperturesin aligned positions or alternate plates are rotated 180* and stackedwith said apertures in offset positions for forming either a straight ortortuous fluid communication path through the projections of saidstacked plates, and a bend formed in each plate spaced between and fromeach pair of said projections for flexure about an axis transverse tothe respective plate longitudinal axis for controlling the distancebetween each projection to compensate for dimensional differences insaid projections for enabling alignment of the projections of saidplates for stacking.
 2. In the heat exchanger core claimed in claim 1, afirst header plate adjacent one end plate of said stacked plates withsaid header plate having a plurality of equally spaced ports eachdefined by a flange projecting from said header plate and correspondingin number, shape and dimension to the open ends of said one end plateprojections for enabling each flange to be received in the open end of arespective end plate projection, a second header plate adjacent theopposite end plate of said stacked plates with said second header platehaving equally spaced apertures therein for receiving the bottom walland a portion of the side and end walls of a respective projection onsaid opposite end plate, a shroud with a flat peripheral face for eachheader plate for forming a respective sealed header chamber inconjunction with a respective one of said header plates, a rolled edgeon each of said header plates for nestingly receiving a respective edgeof the flat face of a respective shroud in response to movement of saidshroud along the longitudinal axis of said plates, locator tabs on saidheader plates for engaging with stops formed on the flat face of therespective shroud to limit said movement to thereby locate said shroudsrelative said header plates, means for providing fluid flow into one ofsaid chambers defined by said one header plate and the respectiveshroud, and means for providing for the flow of fluid out of the otherof said chambers defined by said other header plate and the respectiveshroud.